154. "For this" used instead of "for this reason"
(X) For this he wants to leave.
(O) For this reason he wants to leave.
The phrase "for this" is incorrect. Say "for this reason" or "for that reason".
Also "owing to that" or "because of that".
155. "Better" used instead of "had better"
(X) Better go home at once.
(O) You'd better go home at once.
The correct phrase is "had better". "You had better go" means "It would be a good thing for you to go".
156. "Up and down" used instead of "upstairs and downstairs"
(X) He's up, he's down.
(O) He's upstairs, he's downstairs.
"He's up" means "he's out of bed". He's upstairs (downstairs) means he's on the upper (lower) floor of the building